EP3822061A1 - Method for producing a plastic tank - Google Patents

Abstract

A method for producing a plastic tank, wherein at least one outer layer of the tank wall (1) of the plastic tank consists of a first material, with a reinforcing plate (2), at least partially made of the at least one area, on an outer layer of the tank wall (1) of the plastic tank first material, is attached, characterized in that first the tank wall (1) is provided as a hot semi-finished plate (1 ') that the reinforcement plate (2) is attached to the hot semi-finished plate (1') outside of a shaping tool (3) , in particular is welded on, that afterwards the semi-finished plate (1 ') with the attached reinforcement plate (2) is introduced into the shaping tool (3) and is shaped in the shaping tool (3) to form the tank wall (1) of the plastic tank, whereby the reinforcement plate (2) is fastened more strongly to the tank wall (1), in particular more strongly welded to the tank wall (1).

Description

Field of the invention

The present invention relates to a method for manufacturing a plastic tank.

State of the art

It is known that plastic tanks, which have recently been installed, for example, as fuel tanks in motor vehicles such as passenger cars and trucks, in addition to a number of positive properties, are problematic with regard to possible deformations of the fuel tank. During normal operation of tank systems in motor vehicles, high deformations can occur in certain zones of the tank system. Chaining of pressure and temperature peaks in zones of the tank can, especially in the case of plastic tanks, cause high relative movements of the tank shells and must be limited by design measures.

Support concepts for reducing the undesired deformations of the fuel tanks, which are known from the prior art, mostly use contact points fixed to the body in order to limit deformations of the tank walls. In particular for tank systems that are under pressure, however, these measures are not sufficient and additional measures must be used to reduce deformations. The shell thickness of the tank bladder is often increased or stiffening components are attached to the tank wall in order to limit the deformation. However, the attachment of stiffening components to a Tank wall previously time-consuming and costly and not very flexible with regard to component geometries that can be used for stiffening.

Summary of the invention

It is an object of the invention to provide a method for producing a plastic tank, the plastic tank being protected against deformation. The method should be able to be carried out particularly efficiently and be flexible with regard to the stiffening geometries.

The object is achieved by a method for producing a plastic tank, at least one outer layer of the tank wall of the plastic tank being made of a first material, with a reinforcing plate at least partially made of the first material being attached to an outer layer of the tank wall of the plastic tank in at least one area is, the tank wall is initially provided as a hot semi-finished plate, that the reinforcement plate is attached to the hot semi-finished plate outside of a shaping tool, in particular is welded, that then the semi-finished plate with the attached reinforcement plate is introduced into the shaping tool and in the shaping tool for Tank wall of the plastic tank is formed, whereby the reinforcement plate is more strongly attached to the tank wall, in particular more strongly welded to the tank wall.

According to the invention, a reinforcement plate is applied to a tank wall as a reinforcing element, the application being carried out in two stages: first, the reinforcement plate is only slightly attached outside of a shaping tool. Because the reinforcement plate at least partially consists of the same material as the tank wall, in particular consists of the same plastic or comprises the same plastic, the reinforcement plate can in particular simply be pressed onto the tank wall so that the reinforcement plate is fused or welded to the hot tank wall. The same tank wall with attached reinforcement plate, also known as a "patch", is then shaped in a molding tool into the final shape of the plastic tank, the reinforcement plate being fastened even more firmly to the tank wall or welded to it by the conditions prevailing, in particular pressures or is more strongly fused.

Due to the inventive introduction of the patch or the reinforcement plate outside of the forming tool, the reproducible complexity of the surface geometry of the reinforcement plate and the achievable degrees of deformation are very high.

The term "outer layer" refers to an outer layer of the tank wall and, in the case of a finished plastic tank, can be located on the inside or outside of the container.

The tank wall is preferably made up of multiple layers or multiple layers, but can also consist of a single layer.

Further developments of the invention are given in the dependent claims, the description and the accompanying drawings.

The reinforcement plate preferably consists of a fiber-reinforced plastic, the fiber reinforcement being embedded in a matrix and the matrix consisting of the first material.

The first material is preferably high density polyethylene (HDPE).

The reinforcement plate is particularly preferably a glass fiber fabric.

The hot semi-finished plate is preferably held by a holding device, in particular by means of a negative pressure, while the reinforcement plate is attached to the semi-finished plate outside the shaping tool.

Outside the shaping tool, the reinforcement plate is preferably attached to the semi-finished plate by means of an extendable stamp.

The punch can hold the reinforcement plate by means of a negative pressure. The negative pressure is preferably ended when the reinforcement plate is attached to the hot semi-finished plate. The stamp is then removed again from the semi-finished sheet, in particular withdrawn.

The surface of the stamp is preferably inclined relative to an intended neutral position of the semi-finished plate. In this way, sagging of the hot semi-finished plate can be compensated for and the reinforcement plate can be applied parallel to the relevant section of the semi-finished plate.

The punch is preferably pressed into the hot semi-finished plate in a force-controlled or path-controlled manner in order to fasten the reinforcement plate on the hot semi-finished plate outside of the shaping tool.

The hot semi-finished plate can be trimmed in a cutting tool, in particular before the hot semi-finished plate is provided in order to fasten the reinforcement plate to it.

The semi-finished plate is preferably formed into the tank wall of the plastic tank by deep drawing in the shaping tool, in particular by means of a negative pressure.

Brief description of the drawings

Fig. 1

ist eine schematische Darstellung eines erfindungsgemäß hergestellten Kunststofftanks.

Fig. 2

ist eine schematische Darstellung eines erfindungsgemäßen Verfahrens zur Herstellung eines Kunststofftanks.

Fig. 3

ist eine schematische Darstellung der Anbringung einer Verstärkungsplatte in einem erfindungsgemäßen Verfahren gemäß Fig. 2.

Fig. 4

ist eine schematische Detaildarstellung von ersten Schritten zur Anbringung einer Verstärkungsplatte in einem erfindungsgemäßen Verfahren gemäß Fig. 2.

Fig. 5

ist eine schematische Detaildarstellung von zweiten Schritten zur Anbringung einer Verstärkungsplatte in einem erfindungsgemäßen Verfahren gemäß Fig. 2.

The invention is described below by way of example with reference to the drawings.

Fig. 1

Figure 3 is a schematic representation of a plastic tank made in accordance with the present invention.

Fig. 2

Figure 3 is a schematic representation of a method of manufacturing a plastic tank according to the present invention.

Fig. 3

Figure 13 is a schematic representation of the attachment of a reinforcement plate in a method according to the invention Fig. 2 .

Fig. 4

is a schematic detailed representation of first steps for attaching a reinforcement plate in a method according to the invention according to Fig. 2 .

Fig. 5

is a schematic detailed illustration of second steps for attaching a reinforcement plate in a method according to the invention according to Fig. 2 .

Detailed description of the invention

The local deformation of a tank shell is intended to be reduced by attaching structural components, that is to say reinforcing plates 2, in particular fiber-reinforced structural components. For this purpose, these reinforcement plates 2, structural components or patches can be attached inside and / or outside the tank. Fig. 1 shows such a plastic tank, the tank wall 1 of the plastic tank being partially reinforced by attaching reinforcing plates 2 or patches in various areas. At least one outer layer of the tank wall 1 of the plastic tank consists of HDPE. On the outer layer of the tank wall 1 of the plastic tank, a reinforcement plate 2, which consists at least partially of the same material HDPE, is attached in several areas. The reinforcement plates 2 consist of a fiber-reinforced plastic, the fiber reinforcement being embedded in a matrix and the matrix consisting of the high-density polyethylene.

To produce such a plastic tank, as in Fig. 2 shown schematically, initially the tank wall 1 is provided as a hot semi-finished panel 1 ', wherein the semi-finished panel 1' can initially be an uncut, for example endless, multilayer panel.

The hot semi-finished sheet 1 'is cut in a cutting tool 6 and then made available in order to fasten the reinforcement sheets 2 to it.

Outside a shaping tool 3, in which the shape of the tank shell will later be formed, the reinforcement plates 2 are attached to the hot semi-finished plate 1 ', in particular melted - as in FIG Figures 3 to 5 is shown in more detail.

In the Figures 3 to 5 it can be clearly seen that the hot semi-finished plate 1 'is held by a holding device 4, in particular by means of a negative pressure, while the reinforcement plate 2 is attached to the semi-finished plate 1' outside the shaping tool 3. The semi-finished plate 1 'can be held from above so that it can sag downward, as in the detailed representations Figures 4 and 5 evident.

Outside the shaping tool 3, the reinforcement plate 2 is fastened to the semi-finished plate 1 'by means of an extendable punch 5.

Then the semi-finished plate 1 'with the attached reinforcement plates 2 is introduced into the shaping tool 3 and shaped in the shaping tool 3 to form the tank wall 1 of the plastic tank, as a result of which the reinforcement plates 2 are more strongly attached to the tank wall 1, namely more strongly fused or fused with the tank wall 1 be welded.

The semi-finished sheet 1 'is formed into the tank wall 1 of the plastic tank by deep drawing in the shaping tool 3, in particular by means of a negative pressure, thus preferably by vacuum deep drawing.

The method described is thus based on the positioning and fusing of the matrix material HDPE of the fiber patches or reinforcement plates 2 with the HDPE outer layer material of the tank shell outside of the shaping tool 3.

The merger described takes place in a two-stage process. In a first step, the patch 2 is positioned at a defined point on the semi-finished panel 1 'and attached by contacting the semi-finished product 1' and the fiber patch 2. The subsequent deep-drawing process brings about a permanent fusion of the two materials and an insoluble material bond is formed.

After a hot multilayer board has been produced, it is conveyed to the cutting and processing device 6. After the cutting process of the semi-finished sheet 1 'has taken place, it is received in the holding device 4 and the semi-finished sheet 1' is guided to a device for attaching the fiber patch 2. After the fiber patch 2 has adhered, the semi-finished panel 1 ′, which is now reinforced with the fiber patch 2, is guided to the tool mold 3 and reshaped into its final shape in the molding process.

Fig. 3 shows schematically the attachment of the reinforcement plates 2.

The holding device 4 with the hot semi-finished sheet 1 ′ is brought into an exactly defined position above a punch 5. The fiber patch 2 is positioned on this stamp 5 and is brought into contact with the hot plate 1 'by application. This can be a heated patch or reinforcement plate 2 or at room temperature.

The Fig. 4 shows in a detailed scheme the fastening of a reinforcement plate 2 to a stamp 5 and the positioning of the reinforcement plate 2 or the fiber patch on the semi-finished product 1 '.

The fiber patch 2 is held in position on the die 5 by the application of a negative pressure. This negative pressure is preferably realized by a circumferential groove or by using bores. When the stamp 5 is attached, the negative pressure remains until the positioning is completed. The natural sag of the still partially plasticized multilayer material 1 'is compensated for by a suitable inclination of the punch 5 relative to the neutral position of the semi-finished product 1'. In addition to the shape of the stamp 5, this inclination can also be implemented by mounting the stamp 5 by means of an articulated or ball joint.

Fig. 5 shows in a detailed scheme the fastening of the reinforcement plate 2 to the semi-finished plate 1 'and the initial adhesion process.

To apply the necessary contact pressure, the stamp 5 is pressed into the partially plasticized semi-finished sheet 1 'up to a certain end position in a force or path-controlled manner. For this purpose, the edge areas of the stamp 5 can be provided with a slope. The pressing of the glass fiber patch 2 against the semi-finished panel 1 'can additionally be reinforced by a circumferential vacuum groove or circumferential vacuum bores. In this case, the semi-finished plate 1 ′ is additionally sucked through the vacuum groove or the vacuum bores onto the surface of the stamp 5.

After the pressing time has taken place, the vacuum for fastening the patch 2 is deactivated and the stamp 5 moves back to the starting position without a fiber patch 2.

The semi-finished panel 1 'now reinforced with the fiber patch or the reinforcement plate 2 is fed to the deep-drawing process in which the Application of negative pressure on the tool side results in a permanent material connection between the fiber patch 2 and the tank wall 1 that has now been created.

List of reference symbols

1

Tank wall

1'

Semi-finished panel

2

Reinforcement plate

3

Forming tool

4th

Holding device

5

stamp

6th

Cutting tool

Claims (9)

A method for producing a plastic tank, wherein at least one outer layer of the tank wall (1) of the plastic tank consists of a first material, with a reinforcement plate (2) at least partially consisting of the first on an outer layer of the tank wall (1) of the plastic tank in at least one area Material consists, is attached,
characterized in that first the tank wall (1) is provided as a hot semi-finished plate (1 '), that the reinforcement plate (2) is attached to the hot semi-finished plate (1') outside a shaping tool (3), in particular it is welded on, that afterwards the semi-finished plate (1 ') with the attached reinforcement plate (2) is introduced into the shaping tool (3) and is shaped in the shaping tool (3) to form the tank wall (1) of the plastic tank, whereby the reinforcement plate (2) is stronger on the tank wall (1) is attached, in particular welded to the tank wall (1) more strongly. Method according to claim 1,
characterized in that the reinforcement plate (2) consists of a fiber-reinforced plastic, the fiber reinforcement being embedded in a matrix and the matrix consisting of the first material, the first material preferably being high density polyethylene. Method according to at least one of the preceding claims,
characterized in that the hot semi-finished plate (1 ') is held by a holding device (4), in particular by means of a negative pressure, while the reinforcing plate (2) is attached to the semi-finished plate (1 ') outside the shaping tool (3). Method according to at least one of the preceding claims,
characterized in that outside of the shaping tool (3) the reinforcement plate (2) is attached to the semi-finished plate (1 ') by means of an extendable ram (5). Method according to claim 4,
characterized in that the punch (5) holds the reinforcement plate (2) by means of a negative pressure, the negative pressure preferably being terminated when the reinforcement plate (2) is attached to the hot semi-finished plate (1 '). Method according to claim 4 or 5,
characterized in that the surface of the stamp (5) is inclined relative to an intended neutral position of the semi-finished plate (1 '). Method according to at least one of Claims 4 to 6,
characterized in that the punch (5) is pressed into the hot semi-finished plate (1 ') in a force or path-controlled manner in order to fasten the reinforcement plate (2) on the hot semi-finished plate (1') outside the shaping tool (3). Method according to at least one of the preceding claims,
characterized in that the hot semi-finished plate (1 ') is trimmed in a cutting tool (6) before the hot semi-finished plate (1') is provided in order to fasten the reinforcement plate (2). Method according to at least one of the preceding claims,
characterized in that the semi-finished plate (1 ') is formed into the tank wall (1) of the plastic tank by deep drawing in the shaping tool (3), in particular by means of a negative pressure.

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